1. Field of the Invention
The present invention relates to a protective apparatus of a substrate, a mask that is provided with the protective apparatus, exposing art that uses this mask and device fabricating art.
2. Description of Related Art
In the photolithography process for fabricating an electronic device or the like, an exposure apparatus is used that illuminates a mask with exposure light, and exposes a photosensitive substrate with the exposure light from the mask. The mask is provided with a mask substrate (mask blank) and a protective apparatus that protects the pattern area in order to prevent foreign matter from adhering to the pattern area on the front surface of the mask substrate. The protective apparatus is provided with a pellicle frame that is installed on the mask substrate, and a pellicle that consists of, for example, a transparent, polymer film that is mounted on the pellicle frame (for example, refer to Japanese Unexamined Patent Application Publication No. 2002-296763).
In a conventional mask, when the mask substrate sags under its own weight, sagging occurs in the pellicle of the protective apparatus in correspondence. Recently, as mask substrates have increased in size, the sag amount of the mask substrate, and by extension the sag amount of the pellicle, has increased in accordance with the size of the mask substrate. When the sag amount of the pellicle increases in this way, for example in the case of irradiating detection light on the surface of the pellicle to detect the surface state thereof (for example, the presence of foreign matter), depending on the position on the pellicle, the irradiation condition of the detection light and the detection condition thereof change, leading to the risk of misdetection.
An aspect of the present invention has as its object to provide a protective apparatus and mask that are capable of suppressing sagging of the protective film such as a pellicle, and manufacturing art and conveying art of that mask. Also, an aspect of the present invention has as its object to provide exposing art and device manufacturing art using that mask.